• Journal of the Korean Society for Precision Engineering
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• v.23 no.11 s.188
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• pp.85-92
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• 2006

For the improvement of a conventional railway speed, tilting train(Tilting Train express) is under the development aiming for a maximum speed 180km/h. Compared to the existing conventional rolling-stock, tilting train could take an advantage of speed improvement about $20{\sim}30%$ on curve sections due to the improvement of cowing performance. However, this speed increasement creates a severe load at wheels, thus it is necessary to study the safety of wheel for tilting train preferentially. On the other hand, it is under consideration that the wheel for conventional railway rolling-stock at speeds of 150km/h will be applied to tilting train at speeds of 180km/h. In this paper, we have studied the strength of wheel structure, the geometrical contact characteristics, and the dynamic performance of wheel to evaluate the safety of wheel for tilting train.

• Journal of the Korean Society of Safety
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• v.35 no.4
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• pp.9-14
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• 2020

It is necessary to apply a non-contact high-speed scanning system that can measure in real time in order to prevent the dropping and deformation of the main parts of railway vehicles during high-speed running. Recently, research on a scanning system that detects the deformation state of main parts from a video image taken using a high-performance camera has been actively pursued. In this study, we researched an analysis algorithm of a high-speed scanning system that uses a high-performance camera to monitor the deformation and drop-out state of the main components of the running units equipment in real time.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.206-212
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• 2004

This paper is application of System Assurance(SA) for the rolling stock. As railway systems become more complex, design teams are increasingly under pressure to deliver, design solutions, which integrate both technical and Systems Assurance(SA). Systems Assurance is the application of management methods and analysis techniques to ensure that a design meets Reliability, Availability, Maintainability and Safety (RAMS) criteria. It should be clearly understood that the intent of System Assurance is not just to provide analytical techniques as a metric on performance, but more importantly it should provide a management tool with which to co-ordinate and assure the whole design. System Assurance encompasses the ongoing requirement to consider safety, and RAM through each stage of a Project, from feasibility study through to commissioning and operation. If System Assurance is undertaken properly at feasibility study at the design stages of a Project, the benefits of such analyses can be significant in identifying potential problems early enough for action to be taken before manufacture or installation. At commissioning, RAMS demonstration activities are undertaken to validate the predictive and analytical techniques undertaken during the design.

• Proceedings of the Safety Management and Science Conference
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• 2007.11a
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• pp.503-516
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• 2007

USA has distinct differences of economic policy by a ruling party. And, USA economy has mainly influenced on it of Korea. So, we examine whether a ruling party of Korea has different regime including rate of return in stock market. The Republican Party and Democratic Party have based on Milton Friedman and Keynes economy at each other's economic policy in the USA The Republican Party and Democratic Party have different interest level and excess return on equity, GDP growth rate, unemployment rate. Also, a ruling party of Korea has different regime and economic activity in this paper.

• Journal of the Korea Safety Management & Science
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• v.16 no.4
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• pp.323-330
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• 2014

Various inventory control theories have tried to modelling and analyzing supply chains by using quantitative methods and characterization of optimal control policies. However, despite of various efforts in this research filed, the existing models cannot afford to be applied to the realistic problems. The most unrealistic assumption for these models is customer demand. Most of previous researches assume that the customer demand is stationary with a known distribution, whereas, in reality, the customer demand is not known a priori and changes over time. In this paper, we propose a reinforcement learning based adaptive echelon base-stock inventory control policy for a multi-stage, serial supply chain with non-stationary customer demand under the service level constraint. Using various simulation experiments, we prove that the proposed inventory control policy can meet the target service level quite well under various experimental environments.

• Journal of the Korea Safety Management & Science
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• v.14 no.2
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• pp.137-145
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• 2012

본 연구는 공급자(supplier), 소매상(retailer) 그리고 고객(customer)으로 구성된 2 단계 공급사슬에서 소매상의 관점에서 소매상의 최적 재고정책 결정에 관한 문제를 다루었다. 공급자는 수요 증대를 목적으로 소매상의 주문량에 따라 다단계로 일정기간동안 제품 판매대금에 대한 지불 연기(외상)를 허용하고, 고객의 수요는 소매상의 제품 재고량에 영향을 받는다는 가정 하에 재고 모형을 설계하였다. 모형 분석을 통하여 소매상의 이익을 최대화하는 최적 주문량 결정 방법을 제시하였고, 예제를 통하여 그 제시된 해법의 타당성을 보였다.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1655-1660
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• 2009

At the Rolling-stock, most important thing is thorough maintenance for safety as a mass transit. Recently, many studies of cost down method and acquisition of high reliability have being progressed with considering of safety. Maintenance cost is closely relative to the preventive maintenance. But generally the preventive maintenance is decided in compliance with an experience. So the study of cost down method at the preventive maintenance is difficult. In this study, many results of effectiveness and optimization for the preventive maintenance are checked. Then., it is possible that efficiency preventive maintenance method will be able to suggest.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.38 no.1
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• pp.124-130
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• 2015

In many inventory situations, items for sales are generally stocked in a multiple of variations called stockkeeping units, such as size, color, style, and so on. For better management performance on sales items, proper and effective management is necessary for the stockkeeping units. In dealing with many items and those stockkeeping units, individual inventory analysis for each stockkeeping unit needs large amount of time or cost. Also the individual approach in inventory planning increases the demand variation of an item as the result by combining of demand variations of all stockkeeping units, accordingly the inventory turnover ratio and profitability are dropped down. This research suggests an effective method of systematic control of total stockkeeping units by generating from the total item basis, and shows how to reduce the safety stock and the average inventory with attaining a planned customer fill rate of the item and each stockkeeping units.

• Journal of the Korea Safety Management & Science
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• v.12 no.3
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• pp.215-221
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• 2010

Many researches and projects are actively implemented in the academic world and industrial world in order to increase the productivity through changing utility layout. Effective layout makes the flow of parts and products go on wheels and helps labor forces and utilities to be used efficiently. In this study, we looked at effect on utility layout change through a case of a company making a fuel tank of vehicle in Korea. Due to the layout improvement, this company could have flowshop system on welding line, so the stock in line was decreased, checking the number of stock became easier than before and it was possible to evaluate exact cycle time per unit. Through not only confirming qualitative effect, but also checking quantitative effect such as UPH(Unit per Hour), we obtained the conclusion that the layout improvement increased the productivity.

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.604-609
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• 2003

The fire precautions regulation for Rolling stock in England, France and America concentrate on ensuring of safety in respect of material choosing method and consideration of design. In order to guarantee fire safety in Korean Rolling stocks, it is necessary to establish the fire precautions regulation at the two respects. Korean Standard of product classifies only incombustibility or not. It is not sufficient to classify various materials by testing method for incombustibility of material. Korean Standard to be reserved should be able to cover the smoke density test for small size and classification of the detail grade of material against the reaction to fire